It is abnormal when you hear your engine knocking. Don’t take this lightly, because it seriously damages your engine and proves to be a disaster for your car.

When you drive, this engine knock grows louder. Now you may drive your car despite the knocking sound – but this harms your engine more. And no, it won’t go away on its own.

Instead of waiting for your engine to change its mind and stop knocking – it helps to know how to fix the issue. It’s great for your pocket as it saves your money and time too.

The real problem is that your cylinder fuel ignites prematurely and, that imbalances the air and fuel mixture in it. Because of this, there is unburnt fuel left in your engine.

Spark plugs need to ignite your engine at the right time. When this doesn’t happen, it creates a pinging sound. If not repaired soon, it puts major pressure on your engine.

The pistons of your engine start clanking against the crankshaft – because your engine bearings have worn out.

Luckily, these issues are easy to fix. Read this guide to find out why your engine is making a knocking sound, and how to fix & prevent it for your car.

engine knock

What is engine knocking?
The engine knock or detonation happens because of a major combustion issue. The fuel in your engine doesn’t ignite at the right time – and results in lots of unburnt fuel. These irritating roars that come from your engine will tire out its bearings.

They loosen the pistons in your engine and these pistons start hitting the crankshaft. A major part of this is the uneven air-to-fuel ratio in your engine cylinders. This causes major shock waves to run through it – and might cause cracks in the combustion chamber.

All of these issues grow the pressure and temperature in the cylinders. You’ll notice the engine knock rises – when the air continues to get highly compressed in the engine.

The octane numbers of your engine can help you determine the amount of knocking your engine is experiencing.

engine knock

How to fix the engine knocking problem?

Fixing an engine knock problem is very important to the health of your engine. When this problem persists for a long time, it causes permanent damage to your car engine.

To save yourself from unwanted repair costs, here are some steps that help in fixing your engine knock problem:

  • Use good oil: A good quality oil for your engine keeps it running smoothly. Engine knock can be avoided when your engine is lubricated correctly. Good oil can maintain good viscosity, which makes its thickness work for knocking.
  • Pick an octane booster & check the octane rating: Picking a fuel octane booster increases your fuel’s octane rating. This increases drivability and, also helps clean your car’s combustion chamber.

    Check the octane rating of your fuel – and, replace it with a high-octane fuel. This will stop your engine from igniting before the correct time. If you keep using low-octane fuel, it’ll make your engine knock sounds worse.

  • Maintain coolant levels: If you hear engine knocking sounds, it’s very important to not have low coolant levels. This worsens the engine knocking problem. Besides refilling your engine oil often, maintaining your coolant levels helps your engine run smoother. It stops overheating, which helps fix engine knock issues.
  • Fix your spark plugs: When you notice that your engine’s spark plugs are too old or damaged, it’s best to replace them. This will help your system’s ignition and, get your engine working in no time.
  • Clean the air filter: When your car’s air filter is too clogged, the dirty air/fuel mixture makes it harder for your engine to breathe. Clean your air filter to help your engine function better, and replace it if damaged or not working properly.

  • Engine knock sensor: These sensors will help you detect detonation in your engine. You can also adjust the ignition timing to prevent it. When you already have an engine knock sensor installed and it’s defective, it’ll cause engine knocking sounds.

  • Clean out carbon build-up: There can be an intense build of carbon in the combustion chamber of your engine. When you don’t clean this up, it causes engine knock sounds. Consult a mechanic to professionally get rid of any carbon build-up.

  • Repair engine damage: When you don’t repair the engine knocking for a long time, the extensive damage to your engine increases. Moreover, if you drive with a knocking engine for a long time – your engine could completely shut down. Consult a mechanic soon for small repairs – or get another enginefor your car.

Ways to prevent engine knock problems: 

As the famous saying goes, prevention is better than cure. You can stop the first engine knock before it happens. Follow these steps:

  • Retard ignition timing:Engine knocking happens when your spark plugs light up too soon. When you slow down the rate of their ignition, combustion problems are less likely to occur.
  • Always use high-octane fuel:A high-octane fuel will positively increase your engine’s performance, and increases the temperature of combustion. This helps your engine utilize fuel efficiently, and saves your engine from exploding.
  • Lower compression ratio: It’s important to decrease the compression ratio to reduce engine knocking. Mostly, a compression ratio of 3.5 to 4.0 max. is considered a standard measurement. A higher compression ratio may increase torque, but it isn’t helpful when you have an engine knock.
  • Maintain a balanced air-to-fuel mixture: Check if your vehicle’s carburetor is working properly. It’s important to maintain a balanced air-to-fuel ratio in gas cylinders – or it causes engine flooding. Usually, most systems are good with 13 parts of air to 1 part of fuel ratios – for their engines.
  • Wait for the engine to warm up before driving:When you cold start your engine, it doesn’t have enough time to heat up. This causes engine flooding. Using your engine again can cause vicious knocking sounds from it. So, the best thing to do is wait for your engine to be at an optimal level – before driving. This helps in the good maintenance of your car.

  • Use anti-knocking additives: There are gasoline additives available in the market that decrease engine knocking. This works because they make the fuel’s octane level higher. This increases temperature and triggers auto-ignition.


Engine knock problems happen when engine fuel ignites too soon or at the wrong time. This causes the air-to-fuel ratio imbalance in the gas cylinders. When you see your engine knocks too aggressively, it’s a sign of engine issues. This needs immediate attention.

When you let repairs linger for too long, your engine gets severely damaged. The best thing to do is replace your engine. Check out the best quality used engines – available in the market today! Save money today by getting 100% warrantied and ASE-certified engines.

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Frequently Asked Questions

  1. What does it mean when your engine is knocking?

    When you hear your engine knock, it means that your spark plugs incorrectly ignited at the wrong time. This happens because there is an imbalance of fuel-to-air ratio in its gas cylinders.

Engine knocking is a serious engine issue that needs to be fixed immediately, or it causes damage to your engine severely.

  1. How do you stop the engine from knocking?

    A very common cause of engine knocking is loose bearings. Check your engine bearings to see if they’re still working properly. If they’re damaged, it’s best to replace them. Getting new bearings for your engine will fix its knocking issue.

  2. What is the difference between detonation and knocking? 

Engine knocking has more to do with the imbalance of air-to-fuel ratios in gas cylinders and the noises that your engine makes because of that. On the other hand, detonation deals with the ignition of your engine’s combustion chamber.

  1. What are the types of engine knocks?

    There are different types of engine knocks you may hear. Some of those include light knocking, spark plugs knocking, and crankshaft knocking among many others. These various engine knocks help you identify what is wrong with your engine faster.

  2. Is engine knocking a serious problem?

    Yes, engine knocking causes brutal damage to your engine if not fixed soon. Engine pistons start to hit crankshaft walls – which causes a knocking sound. This happens because of loose engine bearings.

    In that case, you’ll need an engine replacementto get your car back on the road.